"There's No Such Thing as Bad Snow"

They can be fitted quickly – and then provide maximum safety on wintry roads. But before winter tires are ready for volume production, they have to undergo a year-long series of tests: in the Arctic Circle, in New Zealand – and in the Contidrom test center in the Germany state of Lower Saxony. ContiSoccerWorld talked to Dr. Andreas Topp, Head of Winter Tire Development at Continental, about his fascinating field of research.

ContiSoccerWorld:ContiSoccerWorld: Mr. Topp, Eskimos have well over a hundred names for snow. How many types of snow is a tire developer familiar with?

Dr. Andreas Topp

Andreas Topp:Oh, we are well acquainted with a wide range of snow types – but there aren't really quite that many. We also don't have an individual name for each type like Eskimos do. But that's not important. We test winter tires in all parts of the world. In doing so, it is particularly important to provide comparable test conditions wherever we are, be it in New Zealand, Lapland, or Switzerland. This is also why we prepare the tracks accordingly. We don't test various types of snow. Instead we create the right snow conditions wherever possible to enable us to conduct a representative assessment for the wide variety of conditions our customers will encounter.

ContiSoccerWorld:ContiSoccerWorld: So where can we find the world's best snow for testing?

Topp:For us, there's no such thing as good or bad snow. We don't think in these terms. There is dry snow and wet snow, loose snow and densely packed snow – and many types in between. When testing, it is important for us to have a track with stable conditions that is therefore capable of producing reproducible test results. For example, at temperatures of minus two degrees Celsius, the snow is too wet. It quickly forms a thin film of water and this can distort the measured results. We need lower temperatures and a sufficiently thick layer of snow. We don't carry out tire tests on fresh snow, either. Instead, we do them on a specially prepared track. We compact the snow over a large area and then roughen up the surface again. This makes for a homogeneous surface and provides us with comparable test results.

ContiSoccerWorld:But how does this specially prepared snow-covered track in New Zealand relate to bad weather in Germany, for example?

Topp:The typical bad weather we are all familiar with in many European countries is indeed a real challenge. We test the tires on a packed, solid layer of snow. Tests conducted on mixed surfaces wouldn't really yield comparable results. Conditions with a mixture of snow and slush need to be considered as a combination of aquaplaning performance and a snow situation. To assess mixed conditions like this, we thus have to carry out a large number of individual tests under a wide range of conditions. Our Contidrom test center near Hanover is excellent for testing aquaplaning, for example.

ContiSoccerWorld:Let's take the example of Continental's current product for this winter, the test winner ContiWinterContact TS 850. How long was this winter tire tested before it was ready for the market?

Topp:A product like the TS 850 needs around three years of development. Last year, the tire was then subjected to the key tests: on the test rigs, the test tracks, and in real operating conditions in controlled road tests.

ContiSoccerWorld:What basic tests does a tire have to pass in the process??

Topp:Every tire is tested in a wide range of different disciplines. Safety properties are the key criteria for us. That's why we conduct a series of extensive safety tests, for example braking on wet, snowy, icy, and dry roads. Cornering stability – in other words, grip when turning corners – is also highly important as is subjective performance in critical driving situations. A good tire must not only make professional drivers feel safe but must also provide everyday drivers with predictable and well-behaved handling.

ContiSoccerWorld:Is there a specific test that only a really good tire can pass with flying colors?

Topp:Being able to excel at everything is the most difficult challenge. And this is something that only a truly outstanding tire can achieve. It's relatively easy to design a tire that excels in one or two criteria. But coming out on top in every area is the real challenge. The principle behind this is comparable to the difference between a sprinter and a decathlete: Unlike the sprinter, the decathlete has to be the best in all disciplines and not just in the hundred meter events. This is what we must achieve because car drivers need to be safe in all situations.

ContiSoccerWorld:Is it possible that the classic test stage for tires will be completely replaced by sophisticated computer simulations somewhere along the line?

Topp:I doubt it. Modern software is a major assist to technical understanding and in the initial design stages, during which, for example, ideas for the profile are evaluated. However, in the final stage we need to combine all of the different aspects, such as the design, rubber compound, profile, etc. and put the overall concept to the test on the road. This stage always holds a few surprises in store for us. That is why I believe the real snow test is irreplaceable and will continue to be so in the future.

ContiSoccerWorld:Some motorists believe it is not necessary to get winter tires for "the bit of winter there is." What is your view on this?

Topp:The main issue is that winter tires not only perform better on snow, but also on cold, wet surfaces. Thanks to their specific properties, winter tires deal with these conditions much better than summer tires in terms of wet grip, braking, and lateral stability. In general terms, winter tires are ideal for the cold time of year. We therefore not only carry out tests on snow but also in the wet. In this way we are able to create the best performing tread pattern possible for the cold winter months.

ContiSoccerWorld:Winter tires get better every year. They have both lower rolling resistance and better grip than their predecessors. Won't this development reach its limit at some point?

Topp:No, thank goodness! You can see by comparison that each new tire line raises the quality bar. The relevant tire tests conducted every year by car magazines and automobile associations confirm this. What is more, development has picked up considerably thanks to the new tire label and the extremely high competitive pressure over the past year.

ContiSoccerWorld:So how, then, is the new TS 850, for example, even more sophisticated than its predecessor?

Topp:The new ContiWinterContact TS 850tops the snow performance of its predecessor by a further four percent in terms of braking, traction, and handling. At the same time, we have reduced rolling resistance by ten percent and achieved a five percent improvement in wet braking.

ContiSoccerWorld:In the nineties, Continental set new standards by adding silica to the rubber compound. Now there are new approaches. Dandelions, for example, are expected to play a role. What are the future trends in tire development?

Topp:At the moment, there is a great deal going on in the development of raw materials. Take silica, for instance. It's not all the same. There are a large number of different types. The issue of sustainability is also very important. For us, sustainability means using renewable raw materials, among other things. In this context, the use of rubber is an important issue and dandelions have excellent potential as a substitute for rubber. Rubber can also be extracted from old tires. This means not only that old tires are mechanically recycled. In addition, new raw rubber can be produced from special parts of the old tires by means of chemical modification. This rubber can then be fed back into tire production.